1/30/12
There is a cadence to a winter dream. It steeps
within a drop of rain and, lost to touch, there
is an opening eye or a zephyr's smile rising to a
morning's kiss. A rib of day has turned and I
see the pastel cadence in a winter's walk. The
vignettes are in old motions and new hopes,
casting in a blossom moment that opens in a song
with no voice but holds to patterns of the day
for a bird, perhaps, for many birds. The heat
beneath me drifts away until I can not feel the
losing but I hear in the shower, drops cascading
to the passing of time. The bed has become cool.
A raven greets the day and I know it's time to
get up. It's Monday morning.
This week, the walk felt like what a reasonable
Caltech winter bird walk is supposed to feel
like. The trees, with one prominent exception,
weren't dripping with birds and the fields were
devoid of them. Hawks were absent, except for a
single red-shouldered hawk, kee-aahing repeatedly
in the distance and we've been having a very
tough extended time with seeing sparrows of
almost any description. So, what's to like? It
was a walk in contrast. In two of the last three
walks, we ended with below median species counts
and this was no accident. The density of birds
of any description was low. In one of those
walks, we didn't even net a crow until nearly
half way through. Last week was better in that
we were above median and above 20 (21) but the
species total was built off the perils of Pauline
and a lucky draw from the second half of the
walk. This week, we picked up species at a
fairly steady clip and the density of individuals
was much higher than it had been over the last
three weeks, although it was still a bit
sporadic. We had multiple examples of most of
the species we picked up and this holds the
promise for next week. It felt like what a 20+
species walk was supposed to feel like and we
ended up at 22, three above the median of 19.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
There were two highlights. The first of these,
chronologically second, was in an oak by the
Tournament Park restrooms. Vicky noticed a bird
foraging actively but almost always to the upper
side of the leaves so that we were getting only
glimpses of bits of bird. Ashish and I joined
the chase but none of us could net a clear look.
It was tantalizing and frustrating. The bird was
silent but dropping hints like bread crumbs. The
bottom was grayish white but there was no throat
patch. There was stippling along the side and
the wing had at least one arcuate white band and
the legs were dark. The face was a "wild"
interplay of white and black with a warbler's
beak. So, we were eventually, from the flotsam
debris, able to construct a female black-throated
gray warbler. Perhaps, you have been seeing lots
of black-throated grays where you live but this
is big news for us. We haven't seen a
black-throated gray warbler since October and it
was not an unreasonable fear that we might not
see another before the Spring migration, if then.
There was, however, a cost to taking so much time
to build an unimpeachable bird, as Vicky and I
completely lost contact with the rest of the
group. I eventually caught up but Vicky had to
leave the walk before she could relay her triumph
to Alan. I would mark the affair as definitely
worth the price but, if Vicky's bird had turned
into a chickadee or a kinglet, I might have been
giving you a paragraph's worth of sour grapes.
The second highlight of the walk beat in the
heart of Tournament Park. Near the sapsucker
tree, we saw several species of birds clustered
near one spot, probably the most species-rich
view of the month. It was so rich that we were
all having trouble keying into what the next
person was seeing. You would inevitably see
something else in the indicated direction and it
clearly wasn't the species your companion was
describing. We pulled a nice orange-crowned
warbler from the foliage and a mountain
chickadee. The highlight, however, was the
magnificent viewing of a male Nuttall's
woodpecker. You could see the crisp whitish
ladder rungs walking up this bird's otherwise black
back and the broad black shoulder. The bird also
showed excellent side views and head shots.
Ashish got a pretty good picture of the bird,
amazingly good, given the lighting. He was kind
enough to post the photo, so anybody who wants to
can relive the moment or fulfill a need for a
little woodpecker envy.
We seem to be in a time of change. Sightings of
some birds like rock pigeons have dropped
dramatically in the last few years. For others,
like the red-whiskered bulbul, the opposite has
occurred. Nuttall's woodpeckers are in the
latter class. Between 2000 and 2009, we averaged
three Nuttall's sightings a year, clearly a bird
you were never shocked to see but certainly not
one that you went on a walk expecting to find.
In 2010, we had eight sightings, twice the
previous high of four. Last year, we had 15
sightings, nearly doubling the previous best
again. So, in case you are wondering about this
year, pair bonding is starting up about now, nest
excavation (an all male production) will start
around late March or the beginning of April and
egg laying, probably around mid-April, though it
could be a little earlier. The nest may be
active into June, and the fledglings will be fed
through July. Nuttall's like oaks but will take
on other types of trees, especially sycamores,
where oaks are scarce (I've had a pair nesting in
a sycamore in my back yard for the last couple of
years). In late July or early August, the
parents kick the juveniles out of their
territory. Nuttall's sightings at Caltech are
rare in September and this may be related to a
tendency for adult Nuttall's to move up and east
following the breeding season.
It's hard to overstate the importance of a
primary hole nester like a male Nuttall's
woodpecker on the local avian ecology. The
Nuttall's will excavate a nesting hole as you may
expect but he also makes a suite of roosting
holes and some bolt holes for escape from
predators like Cooper's hawks. There are many
secondary hole nesters like tree swallows,
western bluebirds, and starlings that depend to a
large degree on old woodpecker holes, so much so
that they will sometimes try to muscle their way
into an active woodpecker hole. So, a male
Nuttall's carves out multiple holes in his
territory to cover use and loss. That's a lot of
work and requires a lot of protection because of
the intense competition from secondary hole
nesters and, in some places, larger woodpeckers.
This may be part of why a woodpecker is, in
general, so attentive to the young. If you
aren't, somebody may take over your nest or even
kill your chicks as part of trying to take over
your nest. So, what's in it for the woodpecker?
Plenty. The Nuttall's carves a tunnel leading to
a chamber nest, which defeats any large snatch
and fly predator like a raven, who would, I am
sure, develop a fondness for woodpecker eggs if
he could just get at them. Since he can't get
his head in through the tunnel and being a very
smart bird, he doesn't even bother to try.
Instead, he flies over to a more open starling
nest, sticks in his head and pulls out a chick or
he carefully surveys a pine, branch by branch,
locates a band-tailed pigeon nest (he knew it was
in there somewhere), and swipes an egg. It is
perhaps no surprise that the Nuttall's has a much
higher nesting success rate than your average
open nesting bird. One consequence of greater
predator safety and constant vigilance is that
woodpeckers can take much longer to raise their
young. A small nonpredatory open nesting bird,
like a warbler or a hummingbird, moves fast on
the reproduction front, in part to minimize the
probability of a nesting failure. You go from
laying an egg to fledging in about three and half
weeks. With secondary hole nesters, like western
bluebirds or mountain chickadees, it's a little
longer, perhaps four weeks. With primary hole
nesters, it's five or six weeks. Averages for
the Nuttall's are 14 days of incubation, and
26-29 days to fledge and, after that, Nuttall's
woodpecker parents will feed the fledged
juveniles for another month, much longer than
typical of open nesting birds.
If a Nuttall's nest is close to our walk route,
the parents will be by for a feeding several
times an hour and that makes for good sighting
chances over an extended period of time. Last
year, we had a pair of Nuttall's nesting next to
the driveway coming into the Tournament Park
parking lot, which probably had a lot to do with
the unusually high frequency of sightings last
year. Unfortunately, we didn't notice the
nesting hole until very late in the season or we
might have done even better. The presence of an
attractive adult male in Tournament Park on the
cusp of the breeding season suggests that he has
established a local territory and that this may
be another banner year for Nuttall's woodpeckers.
The date: 1/30/12
The week number: 5
The walk number: 1128
The weather: 69°F, partly cloudy
The walkers: Alan Cummings, John Beckett, Ashish
Mahabal, Vicky Brennan, Tom Palfrey, Hannah
Dvorak-Carbone, Kent Potter, Viveca Sapin-Areeda,
Carole Worra
The birds (22):
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Mallard
Bushtit
Yellow-rumped Warbler
Lesser Goldfinch
Red-shouldered Hawk
Ruby-crowned Kinglet
Nuttall's Woodpecker
Red-whiskered Bulbul
Orange-crowned Warbler
Mountain Chickadee
Band-tailed Pigeon
Black Phoebe
Hummingbird, Selasphorus
Gull, species
Black-throated Gray Warbler
Snowy Egret
-- John Beckett
Respectfully submitted,
Alan Cummings
2/3/12
http://birdwalks.caltech.edu/index.html
1/24/12
Leavening humility is something I can recommend
to others but, for the last two weeks, we have
been consuming our own pie of submedian species
counts. I can't say that I much like the taste,
so I am happy to announce that we managed to
break the bitter trend with a better than
mediocre performance, even though it was looking
to be another difficult walk. The birds were
sparsely distributed, although Viveca, Vicky, and
I got a fairly good back view of a juvenile
red-tail; Alan and Kent worked a warbler very
hard and eventually concluded that it was an
orange-crowned. I got a very good view (head,
breast, back, and wings) of an American goldfinch
(poetic justice, given that everybody else in the
group was extolling the beauty of his song, which
I couldn't hear, although I could see him
singing; he took off before anybody else could
get a glass on him). Several of us also got an
excellent view of the ruby crown on a
ruby-crowned kinglet. Usually, the crown on
these birds is hidden unless they are excited or
disturbed. Apparently, having fifty bushtits
fluttering all around you is exciting. We also
saw a lot of acorn woodpeckers in various places
along the route. So much for the early
highlights. Half way through the walk we were
only up to 14 species, about where we had been
the previous two weeks. However, the back half
of the walk was unusually productive with both
"common" birds, like a mourning dove and a
northern mockingbird, and much rarer treats like
a mountain chickadee and a snowy egret. The
chickadee provided a stellar view, probably our
best over the last year, which is saying a lot.
The egret was much less giving. The snowy had
been sighted on Baxter pond on Sunday and Monday
but we failed to see him during the walk. Tom,
however, saw it hanging out on the roof of Baxter
as he returned to his office and e-mailed the
bird in. We were at 21, two above the average of
19. Never you mind what the record is.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
Now, the bird of the week is not so much a
highlight bird as a curiosity and it's motivated
by a simple question: where have all the pigeons
gone? We saw a pigeon on Millikan at the
beginning of the walk and, later, we saw a pair
flying near the north end of campus. A decade
ago, I would see dozens of rock pigeons hanging
around and nesting on Bridge above the driveway
leading up to Arms (they used to be called rock
doves but if you live by the AOU code, you have
to call them pigeons now). Now, there are none.
Caltech sealed them off. You wouldn't think that
this would be defining, as many cities have tried
to reduce pigeon populations through removal of
nesting sites with no success. Until very
recently, rock pigeons were not merely a common
sighting on the bird walk. They were virtually
obligatory. In 2007, we had 47 weeks with a rock
pigeon sighting. This dropped to 42, the
following year, 26 in 2009, 12 in 2010, and 21 in
2011, much of which reflected a small flock of
four birds that frequented Wilson near San
Pasqual so we may be in for another slow pigeon
year. The dramatic drop in Caltech population
and sightings does not appear to be associated
with changes in the local hawk population as
sightings of hawks and, particularly, of Cooper's
hawks, who are always ready for a good meal of
pigeon, show no anti-correlation with sightings
of rock pigeons. The maintenance crew decided to
block off the cavities on Bridge and this caused
some loss of nesting "habitat" but I find it hard
to believe that this would have had a long-term
impact. Pigeons are flexible with nest sites
when they have to be. On the other hand, perhaps
the loss of nests that had been in use for a
decade fledging dozens of pigeons, was
psychologically traumatic, and made the flock
decide to move to a more accommodating
environment. Perhaps, our loss is the Freeway's
gain. I don't know. It's a puzzle.
Pigeons are generally viewed as nuisance birds in
urban areas and they have a strong association
with urban or agricultural interests. So, in a
general sense, we have done it to ourselves.
Wild doves, including wild (as opposed to feral)
rock pigeons, are generally territorial,
especially near nesting sites but, if you are
raising pigeons, you want them to tolerate close
proximity so that you can maximize the number of
birds in your coop. So, what do you do? You
breed out territoriality. That male acting
aggressively in your coop looks like supper. The
genes pick up on this really fast and you soon
end up with birds that can tolerate extremely
close quarters. You breed against territoriality
and, in the blink of a genetic eye, you have
feral birds that are limited only by food
availability and we toss out plenty, often on
purpose. They may be native to Europe, the
Middle East, northern Africa, and parts of Asia,
but they are now the world's bird of urbanity.
You might think that rock pigeons are rather
promiscuous, as you will often see courting
behavior in a flock. Rock pigeons are, however,
socially monogamous and really mean it. Pair
bonds are very strong and there is little
evidence for significant extra-pair
fertilization. All that courting happens because
rock pigeons can breed at six months and can
breed every six weeks, one of the reasons it is
so hard to extirpate them in a particular area.
The ancients had it right. Ishtar, the Assyrian
goddess of Heaven and Earth, is often depicted
holding a couple of pigeons. They were sacred to
Astarte, the Middle East's goddess of love and
fertility. The Greeks and Romans associated them
with Aphrodite and Venus. They are about love,
devotion, and fertility. Rock pigeons were an
early domestication success for urban humans,
starting about 5,000 years ago in what is now
Iraq and we brought them over to this country
very early in the seventeenth century. They
haven't managed to do much with the tundra yet
but they have conquered the rest of North
America, although the populations are closely
associated with human activity and they are
probably one of the few species that actually
would miss us if humanity ever disappeared. Of
course, it's a bit of a two-way street. Pigeons
used to be major sources of protein for humans in
environments that were and are protein
challenged. They are the lab rats of the avian
world. On whom else would we perform
laparoscopically assisted hysterectomies (all
survived the surgery; most did not survive the
surgeon), or bone marrow transplants, or test
drugs? A lot of people spend a lot of time
thinking of ways to mess with rock pigeon minds
and bodies.
I would be remiss if I didn't say something about
homing in rock pigeons. Sometime in the first
few weeks of life, a rock pigeon sets a home
roost as the center of the universe and all
subsequent travels are metered against this
position. They don't migrate but they
nevertheless have a variety of tools they can use
to locate themselves relative to the desired home
roost. They have a mental map of physical
locations complete with olfactory and wind-aided
cues. They know paths of previous flights to
home, have a well-developed sun compass that is
time sensitive (e.g., they can account for
changes in declination of the sun through the
day), and a magnetic compass, apparently built
from nanoparticles of magnetite a few nanometers
across in the upper beak and bundled up into
clusters a micron or two in diameter. If you cart
a rock pigeon twenty miles away, and release him,
he will initially fly off in a semi-arbitrary
direction but then figure out where he is
relative to the center of the universe and adjust
direction to match. Although this phenomenon
was first discovered in rock pigeons, it appears
to be feature of many bird species. You might
say that they all follow their noses.
The date: 1/24/12
The week number: 4
The walk number: 1127
The weather: 65°F, partly cloudy
The walkers: Alan Cummings, Kent Potter, Vicky
Brennan, John Beckett, Tom Palfrey, Viveca
Sapin-Areeda, Carole Worra, Melanie Channon
The birds (21):
Rock Dove
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Yellow-rumped Warbler
Mallard
Orange-crowned Warbler
Black Phoebe
Red-tailed Hawk
American Goldfinch
Ruby-crowned Kinglet
Bushtit
California Towhee
Lesser Goldfinch
Common Raven
Nuttall's Woodpecker
Mountain Chickadee
Snowy Egret
-- John Beckett
Respectfully submitted,
Alan Cummings
1/27/12
http://birdwalks.caltech.edu/index.html
1/17/12
Each time we go on the Caltech birding walk, we
stop at the track south of the gym before moving
on to Tournament Park. We look for sparrows in
the grass and phoebes on the goals and, although
this is not generally a hot spot, the odd
meadowlark keeps us coming back. Of humans, we
see mostly sloggers (slow joggers) but,
occasionally, there is a strong runner and I
begin to see the joy of the wind in an economy of
motion and fluid articulation. It is then that
I begin to appreciate why someone would run
around a track multiple times. It's no longer
mind numbing. You are in a zone. With the bird
walk, we circle around the campus. We go the
same way every week. Round and round the same
circuit. There aren't any endorphins to be had.
We don't run the lap but it's new every time.
This week, the walk was pleasant but the birds
were scarce. We didn't see anything that was
especially rare but the spotted towhee in
Tournament Park was a nice capture. This bird
flushed next to the fencing by the track and
stopped to express his annoyance while in full
view. There was also a family of western
bluebirds between Braun and Beckman, a new life
bird for Melanie. These were our first January
bluebirds since 2007. In the end, however, we
found ourselves with just 17 species. This
rather anemic total is three below 20, the median
for week 3, which is three below the record of
23, and we were three above the record low of 14.
We were in thrall of threes.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
In honor of Melanie's new lifer, I thought it
appropriate to designate the western bluebirds as
the species of the day. The fact that we saw a
family group is promising because these birds
usually establish wintering territories that
cover three acres or so. Since we are in the
middle of the winter and we had an adult male and
female along with what I think was a juvenile
male (male juveniles often overwinter with their
parents; females disperse not long after fledging
but will often find some unrelated adults to
overwinter with and they will generally breed
with a first year male from the same wintering
group), there's a good chance that this group is
wintering in our midst and looking for berries.
We could have a shot at them until March, when
they are likely to move up to higher elevations.
Like many songbirds, habitat loss is the biggest
problem for western bluebirds as a species. They
need insects during the breeding season, berries
in the Fall, and most importantly, a viable nest.
Western bluebirds are secondary hole nesters
(they are partial to abandoned acorn woodpecker
holes). Probably the key to survival of western
bluebirds and most of their problems stem from a
lack of nest cavities due to logging, leading to
a lack of snags (standing dead trees) and dead
limbs, urbanization (leading to a loss of snags
and dead limbs as people get rid of the unsightly
snags and dead limbs, thereby destroying avian
habitat), agriculture, leading to a loss of snags
and dead limbs. They do, however, do very well
with nest boxes. It's not quite that simple
because western bluebirds need relatively open
areas for foraging but nesting is probably the
weakest link for this species. There is habitat
loss because of destruction of dead trees and
limbs and there is competition from other hole
nesters like starlings. On an individual level,
western bluebirds can hold their own against
starlings or just about anybody else for that
matter. They are the bullies of my birdbath.
Starlings are, however, relentless and, when
sufficiently numerous, they can sometimes even
drive acorn woodpeckers out of their primary
nests, a short sighted victory to be sure as
those are the guys excavating the new cavities.
The search for suitable nesting sites by western
bluebirds and dispersal of female juveniles after
fledging probably accounts for the summer
sighting that we occasionally get.
Western bluebirds are examples of cooperative
breeders, as an unrelated year old bird (almost
always a male) occasionally (~7% of the time)
helps to feed the nestlings. This is a good
deal for the breeding pair because more eggs will
be laid, more chicks fed, and more nestlings
fledged if there is a helper. What's in it for
the helper is less clear as a helper doesn't gain
any later breeding advantages and waiting a year
to breed significantly reduces his lifetime
fecundity but maybe it's as simple as not finding
a mate. Western bluebirds are socially monogamous
and mate for life but about half of the breeding
females will have an extra-pair egg in her
clutch. This is generally due to a carefully
choreographed encounter with an older male, who
provides nothing except the liaison.
The date: 1/17/12
The week number: 3
The walk number: 1126
The weather: 57°F, sunny
The walkers: John Beckett, Melanie Channon,
Viveca Sapin-Areeda, Carole Worra, Vicky Brennan
The birds (17):
Mallard
Yellow-rumped Warbler
Anna's Hummingbird
Lesser Goldfinch
Black Phoebe
American Goldfinch
Band-tailed Pigeon
Spotted Towhee
House Finch
Ruby-crowned Kinglet
Bushtit
Yellow-chevroned Parakeet
Orange-crowned Warbler
American Crow
House Sparrow
Western Bluebird
Common Raven
-- John Beckett
Respectfully submitted,
Alan Cummings
1/23/12
http://birdwalks.caltech.edu/index.html
1/9/12 (revised to add a Raven)
It started as a lowing call, a nervous tally, a
shattering of the unspoken dreams of a 30 bird
day and it left a handful of clotted feathers
from a clouded memory and a residue of tremulous
anxiety. Alan knew the record high for week 2.
It was 32 species, one of the biggest Caltech
bird walks of all time. What he didn't know was
what the record worst score for week 2 might be
and this was an uncertainty that gnawed. It had
seemed so promising, a nice day, perhaps
unseasonably warm, but nice. Others must have
thought so too for we had nine enthusiastic
walkers. Surely, we were heading for record
territory. Maybe we were, but it was soon clear
that we weren't flirting with a record high.
Record lows during the first quarter of the year
bounce around semi-randomly between 10 and 15 and
here we were, at 12 species, rumbling up Wilson.
Maybe, we were safely above the low. Maybe, we
weren't and, if we weren't, we might be in
trouble. Generally, the number of new species we
pick up on the second half of the walk is a small
fraction of what we obtain from the first half.
Partly, this reflects repeating species we've
already seen (i.e., the second half of the walk
would be much more productive for "new" species
if we did it first) and partly this reflects the
basic fact that the best birding on campus is to
be found in the first half of the walk. So, we
approach our standard house sparrow hunting
grounds, the sheffleras outside the entrance to
Braun and I meet the biggest surprise of my
tenure of two years on the bird walk. The
sheffleras didn't yield any sparrows but Matt saw
a sparrow-like bird zip into the small row of
Indian hawthorns in the middle of the walkway
leading up to Braun. Perhaps, this was a house
sparrow. Perhaps, it was something a little more
exotic. Whatever it was, we had it surrounded
with half a dozen birders covering every possible
exit. We watch and we pish. Nothing works.
Twigs and leaves are rustling but we can't coax a
bird to the surface. The cover is too dense to
make out the speciation of any bird in the
interior and nobody is talking. Suddenly, Alan
bats a bush. This was an utterly desperate act.
Most birders, including Alan, frown on overt
attempts to flush a bird because this forces the
bird to consume energy and any flushing bird is
potentially at an enhanced risk for predation
once exposed. Alan nevertheless sweeps his hand
across the bushes again and two house sparrows
burst out, flying over to the foundation plants
lining Braun. Alan bats the bushes a third time
and three house sparrows flush. We had another
species. We pick up some American goldfinches in
nearby trees. We were at 14 but were we safe
from infamy? Viveca sees a soaring turkey
vulture, a nice capture, as we continue north on
Wilson, which brought us, most likely into fairly
safe territory. By the end of the walk, we had a
total of 17 species. The median is 19 and we
failed to get there, but we did end up some
distance above 11, which turns out to be the
previous and still record low for week 2.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
I think, since we had such a difficult walk from
an avian perspective, that I will choose one of
the least of our captures as the bird of the
week. In the Maintenance yard, there was a
single clear call from a bulbul followed, almost
immediately, by a single clear "bulbul!" call
from Hannah. That's it, the end of the story.
There was no wonderful view to describe, no song,
no careful working of a tree, trying to get a
definitive look, no mystery. Nevertheless, this
vignette provides me with everything I need. The
red-whiskered bulbul is the bird I feel like
talking about and we had one.
If you look at Alan's database and plot the
number of bulbul sightings by year, you will find
a striking pattern. For the first twenty years
of the Caltech birding walk, sightings were quite
rare, averaging one bird every four years. In
2006, we had one sighting, the first since 2004.
In 2007, we had two sightings, the first time
ever for back-to-back bulbul years. In 2008, it
was 6, in 2009, it was 16, in 2010, we had 23,
and in 2011, it was 24. Red-whiskered bulbuls
had gone from next to nothing to one of our dozen
most common birds in just four years. Since most
of our bulbul "sightings" are, as was the case
this week, identifications via the unmistakable
vocalization, this means that we are capturing
the invasion of an area near campus that is
within our hearing range for these birds, perhaps
a buffer zone encompassing two or three yards
deep beyond the campus perimeter. There is
little question that bulbuls are expanding out of
a core area centered in the Huntington gardens
and we have just witnessed the wave passing by
the southern end of campus.
The first bulbul sightings at the Huntington were
in 1968, so why has it taken so long for bulbuls
to make the 1-2 km journey? Bulbuls are invasive
when the local habitat is viable but bulbuls are
also fairly indolent invaders. They were
released in Melbourne, Australia in the 1880s and
expanded their range by just 100 km over the
ensuing century. The Huntington bulbuls had an
additional problem that their Aussie cousins
didn't have to contend with. In 1968, there were
five bulbuls sighted on the grounds of the
Huntington gardens. In 1968, there were five
bulbuls shot on the grounds of the Huntington
gardens. Several to a couple dozen bulbuls per
year were killed through the 1970s in and near
the Huntington by field agents of the Los Angeles
County Department of Agriculture, using shotguns,
pellet guns and slingshots. Bulbuls were and are
listed as destructive agricultural pests by the
state and the local Agriculture department took
this to mean that it was desirable to kill feral
bulbuls whenever and wherever they popped up.
Finally, in 1985, the then director of the
Huntington Library refused to grant access to the
agricultural agents and, in the ensuing standoff,
the county decided that it would reserve the
right to crash through the front gate with guns
blazing but, in the interim, would undertake a
study to determine just how much the bulbuls
threatened LA county crops. As near as I can
determine, the study was never completed or,
perhaps, even started and the eradication program
has not been reinstituted. As much as I like
those fruity voices, I can't say that I think the
county agents were wrong to attack this
introduced species. Bulbuls compete with native
migratory frugivores like hermit thrushes and
cedar waxwings for berries (also western
bluebirds to some extent) and this likely adds to
already substantial stresses for these native
bird species. On the other hand, if I was
worried about avian induced crop damage, I would
have put my efforts into containing the starling
population before putting much effort into
killing bulbuls but governmental organizations
work in mysterious ways.
If you do a histogram by week of bulbul sightings
over the last five years from Alan's database,
you will find a broad peak between weeks ~8 and
~24, centered around week 16 and another, much
sharper, peak with a maximum around week 40.
Remember that our sightings are mostly
vocalizations and that bulbuls most strenuously
vocalize when they are courting and defending
territory. So, it seems likely that our bulbuls
have a major breeding season between late
February/early March and mid-June with another,
shorter, session in mid-August through September,
presumably to take advantage of the Fall berry
crop. A similar pattern is observed in southern
India, where red-whiskered bulbuls are native
(they are native throughout southern Asia). The
main breeding season is December to June with a
second breeding period in September, following
the monsoons. We have a lot of pools and fake
streams, which bulbuls like, lined with
berry-bearing bushes, which bulbuls like. We
have a modest predator population, which bulbuls
like, and a moderate supply of insects, which
bulbuls like when the berries are in short
supply. Judging from the data, our bulbuls are
here to stay and breeding happily two or three
times a year. Enjoy the concert.
The date: 1/9/12
The week number: 2
The walk number: 1125
The weather: 72°F, sunny
The walkers: Alan Cummings, John Beckett, Viveca
Sapin-Areeda, Hannah Dvorak-Carbone, Carole
Worra, Ashish Mahabal, Kent Potter, Matt
Bradford, Vicky Brennan
The birds (18):
House Sparrow
Mourning Dove
House Finch
Anna's Hummingbird
Acorn Woodpecker
American Crow
Mallard
Yellow-rumped Warbler
Red-whiskered Bulbul
Lesser Goldfinch
Ruby-crowned Kinglet
Bushtits
Downy Woodpecker
Black Phoebe
Turkey Vulture
American Goldfinch
Cedar Waxwing
Common Raven
-- John Beckett
Respectfully submitted,
Alan Cummings
1/13/12
http://birdwalks.caltech.edu/index.html
1/3/12
There are times when you know that a new record
for the week is in the offing. Just capture
another species or two and you are there. You
look. You listen and the birds, however
reluctant, are sought with a desperate vigor. It
becomes a bit of a game. Sometimes, you can even
transform a bird into an entirely different
species. I once managed to turn a crow into a
pigeon. Fortunately, this type of magic only
works on yourself and does not will the
acquiescence of other walkers. If you are to
make that record, you will have to find that new
real bird. On other occasions, you don't know
what the record is and you take the birds as they
come, not realizing that you have landed just shy
or just ahead of the record. This week was in
the latter category. We knew that the record was
above 20 but it could have been, for all we knew,
21 or 29. So, we ended the walk with 22 species,
but Viveca e-mailed in an orange-crowned warbler
seen just after separating from us near the end
of the walk. This left us at 23. The record for
week 1 WAS 22. We have a new record at 23 and an
excellent start to the new year.
See the plots at
http://birdwalks.caltech.edu/bird_data/species_time.html
and
http://birdwalks.caltech.edu/bird_data/two_plots.htm
There were a number of highlights. We picked up
a female western tanager near the parking lot for
Tournament Park. Also, Hannah and Viveca both
got flash-by views of a vireo near Morrisroe,
picking up wingbars (hence not a warbling vireo)
and a general sense of gray (probably not a
Hutton's vireo, for which one would have expected
a flash view to yield a sense of buff or brown,
although of course you would then have the
kinglet versus vireo issue to deal with). This
is likely the Cassin's we have been seeing in
this location for the last couple of weeks but
neither Hannah nor Viveca could commit to a
Cassin's. They didn't see any yellow wash along
the side, raising the exciting possibility of a
plumbeous vireo, which would have been a
seriously rare sighting for Caltech, but they
were also unsure, given the limited exposure
time, that there was no yellow to be had. We had
a vireo species.
The baseball field is usually the source of a
bird or two but several times a year, it yields
something really unusual like a meadow lark or
even something spectacular, like an American
pipet or a whimbrel. This week, several birds
congregated near the southwest corner but it
wasn't possible, without a spotting scope, which
we didn't have, for us to determine the species
with any degree of confidence. Speculation was
running between house finch and western bluebird
but this was based on not much beyond a tinge of
blue or red. When this happens, Alan asks for a
volunteer or two to mount an expedition to get a
closer look while the rest of the group moves on
to the track and Tournament Park. Sometimes,
somebody just heads off before he can suggest it
(he has us well trained). Hannah headed for the
corner while Viveca worked her new 10X Nikon
binoculars from the fence. The rest of us moved
on. When they caught up with us, they reported
not one but four new species, western bluebird,
Say's phoebe, house finch, and white-crowned
sparrow. Each in its own way is deserving of
being the bird of the week ,but I will take the
Say's and hope to see the others again over the
next few weeks.
The Say's phoebe is one of those birds that has
received much less study than it deserves. They
are aridity specialists, the only flycatcher and
one of only a dozen species to inhabit the below
sea level portions of Death Valley on a resident
basis. We pick them up as wintering birds with
an arrival at Caltech around week 40-43 (early-
to mid-October), about the same time we start to
see kinglets and yellow-rumped warblers.
However, they leave Caltech by week 10
(mid-March), well before most wintering birds,
including other insectivores like the yellow-rump
warblers. Our Say's phoebes are probably coming
from the desert interior to the east and south
although there may be some contribution from the
Pacific northwest (there's at least one record of
a bird from Washington turning up in Santa
Barbara). Our sightings tend to be sporadic from
year to year but an individual can be quite
reliable as they tend to like certain perches
and, perhaps more importantly for us, they tend
to keep a schedule. A couple of years ago, a
Say's decided that he really liked the soccer
goal and we picked him up every week for several
weeks. Unfortunately, the goal was taken down
and we never saw him again, even though there
were other perfectly goodlooking perching spots
in the same vicinity. I guess that none of them
was just right.
Death comes to each of us in its own time but
with small birds it usually comes within a small
number of years from one of many different
causes, most of them rather unpleasant. If you
don't starve to death in the nest, get killed by
parasites, tossed out of the nest by a cowbird,
or pulled out by a raven, then you get to fend
for yourself. This often means starving to death
in your first year. Even if you get plenty to
eat, you may still be killed by a hawk (if you're
having a good year, they are probably having a
good year, too), by some virus, or by human
intervention. We supply killer pesticides and
herbicides, killer domestic cats, killer windows,
killer wind vanes, killer TV and radio towers,
killer power lines, and killer cars. This week,
Melanie informed me that the resident black
phoebe, who forages in front of Arms, was dead.
This was a young bird, based on the easy perches
he tended to use, but he had already supplied the
Caltech bird walk list with a black phoebe on one
or two occasions. I liked him and enjoyed
watching him forage. I don't know what killed
him but I can tell you that he seemed to be a
successful flycatcher. My suspicion is that
Caltech groundskeepers have been poisoning the
insects he fed on because of the new plantings
and these, in turn, poisoned and, ultimately,
killed our black phoebe. God may have seen our
phoebe falling from a tree but Caltech may have
made it happen.
The date: 1/3/12
The week number: 1
The walk number: 1124
The weather: 82°F, partly cloudy
The walkers: Alan Cummings, Viveca Sapin-Areeda,
Carole Worra, Hannah Dvorak-Carbone, Kent Potter,
John Beckett, Vicky Brennan
The birds (23):
Scrub Jay
Northern Mockingbird
Mourning Dove
House Finch
Anna's Hummingbird
American Crow
Black Phoebe
Yellow-rumped Warbler
Snowy Egret
Lesser Goldfinch
Dark-eyed Junco
Ruby-crowned Kinglet
Western Bluebird
White-crowned Sparrow
Say's Phoebe
American Robin
Western Tanager
Red-tailed Hawk
Vireo Species
American Goldfinch
Downy Woodpecker
Common Raven
Orange-crowned warbler
-- John Beckett
Respectfully submitted,
Alan Cummings
1/8/12
http://birdwalks.caltech.edu/index.html